/*
 * $Header: /l/extreme/cvs/codes/XPP3/java/src/java/xpath/org/xmlpull/v1/builder/xpath/jaxen/function/StringFunction.java,v 1.2 2005/08/11 22:44:02 aslom Exp $
 * $Revision: 1.2 $
 * $Date: 2005/08/11 22:44:02 $
 *
 * ====================================================================
 *
 * Copyright (C) 2000-2002 bob mcwhirter & James Strachan.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions, and the disclaimer that follows 
 *    these conditions in the documentation and/or other materials 
 *    provided with the distribution.
 *
 * 3. The name "Jaxen" must not be used to endorse or promote products
 *    derived from this software without prior written permission.  For
 *    written permission, please contact license@jaxen.org.
 * 
 * 4. Products derived from this software may not be called "Jaxen", nor
 *    may "Jaxen" appear in their name, without prior written permission
 *    from the Jaxen Project Management (pm@jaxen.org).
 * 
 * In addition, we request (but do not require) that you include in the 
 * end-user documentation provided with the redistribution and/or in the 
 * software itself an acknowledgement equivalent to the following:
 *     "This product includes software developed by the
 *      Jaxen Project (http://www.jaxen.org/)."
 * Alternatively, the acknowledgment may be graphical using the logos 
 * available at http://www.jaxen.org/
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE Jaxen AUTHORS OR THE PROJECT
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * ====================================================================
 * This software consists of voluntary contributions made by many 
 * individuals on behalf of the Jaxen Project and was originally 
 * created by bob mcwhirter <bob@werken.com> and 
 * James Strachan <jstrachan@apache.org>.  For more information on the 
 * Jaxen Project, please see <http://www.jaxen.org/>.
 * 
 * $Id: StringFunction.java,v 1.2 2005/08/11 22:44:02 aslom Exp $
 */


package org.xmlpull.v1.builder.xpath.jaxen.function;

import org.xmlpull.v1.builder.xpath.jaxen.Context;
import org.xmlpull.v1.builder.xpath.jaxen.Function;
import org.xmlpull.v1.builder.xpath.jaxen.FunctionCallException;
import org.xmlpull.v1.builder.xpath.jaxen.Navigator;

import java.util.List;

/**
 * <p><b>4.2</b> <code><i>string</i> string(<i>object</i>)</code>
 *
 * @author bob mcwhirter (bob @ werken.com)
 */
public class StringFunction implements Function
{
    
    public Object call(Context context,
                       List args) throws FunctionCallException
    {
        int size = args.size();

        if ( size == 0 )
        {
            return evaluate( context.getNodeSet(),
                             context.getNavigator() );
        }
        else if ( size == 1 )
        {
            return evaluate( args.get(0),
                             context.getNavigator() );
        }

        throw new FunctionCallException( "string() requires one argument." );
    }
    
    public static String evaluate(Object obj,
                                  Navigator nav)
    {
        if ( obj == null )
        {
            return "";
        }
        if ( obj instanceof String)
        {
            return (String) obj;
        }
        else if ( nav.isElement( obj ) )
        {
            return nav.getElementStringValue( obj );
        }
        else if ( nav.isAttribute( obj ) )
        {
            return nav.getAttributeStringValue( obj );
        }
        else if ( nav.isText( obj ) )
        {
            return nav.getTextStringValue( obj );
        }
        else if ( nav.isProcessingInstruction( obj ) )
        {
            return nav.getProcessingInstructionData( obj );
        }
        else if ( nav.isComment( obj ) )
        {
            return nav.getCommentStringValue( obj );
        }
        else if ( nav.isNamespace( obj ) )
        {
            return nav.getNamespaceStringValue( obj );
        }
        else if (obj instanceof List)
        {
            List list = (List) obj;
            int  size = list.size();

            if ( size > 0 ) {
                // the XPath string() function only returns the
                // string value of the first node in a nodeset

                return evaluate( list.get(0),
                                 nav );
            }
        }
        else if ( obj instanceof Boolean )
        {
            return obj.toString();
        }
        else if ( obj instanceof Integer )
        {
            return obj.toString();
        }
        else if ( obj instanceof Double )
        {
            Double num = (Double) obj;
            
            if ( num.isNaN() )
            {
                return "NaN";
            }
            else if ( num.isInfinite() )
            {
                if ( num.intValue() < 0 )
                {
                    return "-Infinity";
                }
                else
                {
                    return "Infinity";
                }
            }
            else if( num.floatValue() == num.intValue() ) // strip .0
              {
              return Integer.toString( num.intValue() );
              }
            else
            {
                return num.toString();
            }
        }

        return "";
    }
}
